Control apparatus for fuel burning apxliances



v. WEBER 3,213,922

CONTROL APPARATUS FOR FUEL BURNING APPLIANCES Oct, 26, 1965 2 Sheets-Sheet 1 Filed Sept. 29, 1958 Oct. 26, 1965 v. WEBER 3,213,922

CONTROL APPARATUS FOR FUEL BURNING APPLIANCES Filed Sept. 29, 1958 2 Sheets-Sheet 2 United States Patent Office 3,213,922 Patented Oct. 26, 1965 3,213,922 CONTROL APPARATUS FOR FUEL BURNING APPLIANCES Victor Weber, Greensburg, Pa., assignor to Robertshaw Controls Company, Richmond, Va., a corporation of Delaware Filed Sept. 29, 1958, Ser. No. 763,892 12 Claims. (Cl. 158-140) This invention relates to control apparatus for fuel burning appliances and, more particularly, to apparatus of the type adapted to control the flow of gas to a gas burner in such a manner that:

(1) Gas is prevented from flowing to the burner when there is no flame burning which can ignite gas flowing from the burner; and

(2) Gas flow to a burner is interrupted if the flame, which ignited the gas flowing from the burner, goes out.

One object of this invention is to reduce the vertical depth of a fuel control valve to make such a valve especially useful in installations where such a reduced depth is desirable.

Another object of this invention is to utilize a temperature responsive means which is provided with a small, simplified temperature sensitive portion especially adapted to be susbtantially enveloped by a flame and to be rapidly responsive thereto.

Another object of this invention is to simplify the details and arrangement of parts within a valve for controlling the flow of gas.

A further object of this invention is to facilitate and simplify the installation of a valve and a pilot assembly within an appliance provided with a gas burner.

In accordance with one feature of this invention, a temperature responsive means is provided with a capillary tube which has a uniform outer diameter, within the limits of manufacturing tolerances, throughout the entire length thereof. One end of the capillary tube is formed with a temperature sensitive portion which comprises an interior chamber having a larger internal diameter than that of the capillary bore of the capillary tube. The length of such a chamber, and the relatively small outer diameter of the tube surrounding the chamber, are especially adapted to be disposed within the path of a small flame which substantially envelops the temperature sensitive portion and makes the same rapidly responsive to changes in the flame.

In accordance with another feature of this invention, the temperature responsive means is provided with an expansible power element which is disposed within a flow passage in a valve casing and actuates a lever system to cause a valve means to open and close in response to movement of the temperature responsive power element. The lever system and the power element are supported by a single connecting means within the flow passage.

In accordance with another feature of this invention, the valve is formed with a somewhat elongated casing and has an outlet, extending in a direction transverse to the elongated direction, which is especially adapted to be connected to the mixing chamber of a gas burner so that it is discharged directly through an orifice in the outlet into the mixing chamber. The elongated shape of the valve reduces the vertical depth required and allows such a valve to be installed in installations having a shallow vertical depth between the end of a mixing chamber and an oven wall.

In accordance with another feature of this invention, the valve and temperature responsive means are operatively connected to a novel pilot assembly which comprises a bracket having a standby pilot and an igniter pilot mounted thereon, as well as the temperature sensitive portion of the temperature responsive means, which bracket is disposed adjacent to the gas burner so as to achieve the general object of this invention.

Other objects and advantages of this invention will be apparent from the following description taken in connection with the accompanying drawings wherein:

FIG. 1 is a schematic view of a heating system embodying this invention;

FIG. 2 is a partial cross-sectional view of a detail shown in FIG. 1;

FIG. 3 is a side elevational view of a portion of a system incorporating the device shown in FIG. 2; and

FIG. 4 is a front elevational view of the device shown in FIG. 3.

A heating system is shown in FIG. 1 for the purpose of illustrating how the invention, as hereinafter described, may be applied. It should be understood that this invention is not necessarily limited to such a system and can readily be applied to other systems by obvious expediencies. Gas is supplied to a burner 10 from a gas supply line 12 through control valve 14, pipe 15, and valve 16. Valve 14 may be a manually operated type which provides 'on-oif control and regulation of flame height, a manual thermostatically operated type which after being turned on automatically regulates the burner, or a thermostatic type which provides continuous control of an appliance such as a water heater. A standby pilot 18 is supplied with gas from supply line 12 through gas line 20 and an adjustable valve 22 which is used to regulate the height of the flame at pilot 18. An igniter pi-lot 24 is disposed adjacent standby pilot 18 and is connected by a gas line 26 to valve 14. By opening valve 14, gas is supplied to igniter pilot 24 which, upon flowing therefrom is lit by the flame at standby pilot 18. Temperature sensitive means 28 has a portion thereof disposed so as to be actuated by the flame from igniter pilot 24 and is used to control valve 16 in a manner hereinafter described.

As shown in FIG. 2, valve 16 is provided with a generally elongated casing 30 comprising casing member 32, cap 34 and plate 36. Cap 34 is threadably received in casing member 32 and has a gasket 38 disposed therebetween to form a fluid-tight seal. Plate 36 has a gasket 37 disposed between the same and casing member 32 and is connected thereto by a plurality of screws 42.

Casing 30 is formed with an inlet 40, an outlet 43, and an elongated chamber or flow passage 44 extending between inlet 40 and outlet 43. A partition 46 is formed integral with casing member 32 and extends across chamber 44. Partition 46 is formed with an aperture or flow passage 48 therein and an annular valve seat 50.

A double threaded-end connector 52 is threadably received at one end thereof in casing member 32 at outlet 43. A hood 54, having a throttling orifice 56 in the end thereof, is threadably received on the other end of connector 52 and cooperates with a needle valve member 58 to restrict the flow of gas through valve 16. Hood 54 may be rotated to move orifice 56 relative to needle valve 58 to adjust the flow of gas to burner 10.

A valve member 60 is provided with a ring 62 of flexible material which is engageable with valve seat 50 to prevent gas from flowing from inlet 40 to outlet 43. An axially extending hub 64 has a retaining ring 66 mounted thereon to hold ring 62 in place. Hub 64 is formed with a bore 68 and has a guide cap 70, provided with a clip periphery, mounted at the other end thereof.

A projection 72 is formed integral with cap 34 and has a hollow central portion adapted to receive one end of a guide pin 74. Pin 74 is formed at the other end thereof with an enlarged section which is slightly less in diameter than the bore 68 and acts as a guide, in conjunction with cap 70, to limit the movement of valve member 60 to a vertical plane, as viewed in FIG. 2, which movement is generally transverse to chamber 44. A helical spring 76, held in compression, extends from casing 30 into contact with valve member 60 and biases the same towards a closed position with valve seat 50.

Thermally responsive means are provided for moving valve member '60 between positions and generally com- .prises a temperature sensitive means 28 and an expansible. power element 80. Temperature sensitive means 28 .comprises a relatively flexible capillary tube 82 having a capillary bore 84 extending substantially throughout the length thereof. A bulb 78 is formed at the outer end of tube 82 by counterboring the end thereof, as for example by drilling, to form an enlarged chamber bounded by a counterbore 86 having a greater internal diameter than that of capillary bore 84. The outer end of tube 82 is sealed as shown at 88, as for example by swaging and welding. A wire 90 is disposed within capillary bore 84 and extends substantially throughout the length thereof.

The expansible power element 80 is formed from a pair of shallow, cup-shaped flexible diaphragm members 92 and 94 which are joined together near the outer peripheries thereof to form an expansible chamber therebetween. The power element 80 is connected to the capillary tube 82 by a connector 96 which is adapted to receive the open end of tube 82 and be permanently attached thereto in a fluid-tight seal by welding. Connector 96 has an axial bore formed therethrough which is disposed in alignment with an aperture in diaphragm 92 so that the bore communicates with the space between diaphragm members 92 and 94. The inner end of connector 96 is permanently attached to diaphragm 92.

A stud 98 is welded to the lower diaphragm member 94 and is formed with an axial bore which communicates with the space between diaphragm members 92 and 94. The thermally responsive means is charged, through this axial bore, with a temperature sensitive fluid, after which a ball 100 is welded over the end of theaxial bore to form a fluid-tight seal.

It is preferable that the temperature sensitive means 28 be charged with mercury and that the parts in contact with the mercury be formed of a stainless steel which is insoluble in the mercury at the elevated temperatures expected to be encountered during operation. The wire 90 forms a filler for the capillary bore 84 to minimize the necessary amount of mercury and to act as a compensating means for ambient temperatures existing between the bulb 78and the expansible power element 80. When the mercury in bulb 78 is heated and it reaches a temperature in excess of its vaporization point, the vaporized mercury causes rapid flow of the liquid mercury through the capillary tube 82 into the space between diaphragm members 92 and 94. Since diaphragm member 92 is held relatively stationary with respect to casing 30, diaphragm 94 moves downwardly, as viewed in FIG. 2, and causes ball 100 to move therewith, A decrease in the temperature of the mercury within the temperature sensitive means 28 causes mercury vapor therein to contract and return to the liquid state whereupon some of the liquid mercury flows back into bulb 78 from the expansible power element and ball 100 moves upwardly, as viewed in FIG. 2. I A U-shaped support bracket 102 is disposed within chamber 44 and has an aperture formed in the end wall thereof through which connector 96 extends. A shoulder 104 formed on connector 96 underlies bracket 102 and forces the same into engagement with an annular ridge 106 formed on casing member 32. A nut 108 threadably engages connector 96 and holds bracket 102 and expansible power element 80 within chamber 44.

The legs of bracket 102, only one of which is shown in FIG. 2, have a pair of fulcrum members 110 and 112. A lever .114 is formed with a shallow, apertured depression intermediate the ends thereof and is adapted to receive a threaded adjusting screw 116 which abuts ball 100. One end of lever 114 is pivoted about fulcrum and the other end engages one end of a lever 118. Lever 118 is pivoted about fulcrum 112 and has an aperture 120 formed therein through which access may be had to adjusting screw 116 when plate 36 is removed from casing 30. Lever 118 contacts valve member 60 at point 122. The legs of bracket 102 prevent lateral displacement of levers 114 and 118.

A helical spring 124 extends between levers 114 and 118 and serves to bias the same apart in such a manner that lever 114 is held in contact with ball 100 and lever 118 is held in contact with fulcrum 112. It should be noted that spring 76 tends to bias the lever 118 in a clockwise direction about fulcrum 112 and lever 114 in a clockwise direction about fulcrum 110. The screw 116 provides an adjusting means by which, one, variations in manufacturing tolerances may be compensated for, two, the maximum opening of valve member 60 can be changed, and three, the temperature at which valve member 60 begins motion upwardly can be varied.

In operation, increases in temperature of sensing means 78 above the vaporization point of the mercury cause power element 80 to expand whereupon ball 100 rapidly moves downwardly, as shown in FIG. 2, causing levers 114 and 118 to pivot in counterclockwise directions causing valve member 60 to rapidly disengage from valve seat 50. Decreases in temperature of the mercury cause power element 80 to contract whereupon return spring 76 causes valve member 60 to move at the same rate as the levers 118 and 114 move in contact with ball 100 until the valve means, comprising valve member 60 and valve seat 50, is closed.

As shown in FIGS. 3 and 4, the burner 10 is supported on an oven or range wall 126 by a bracket 128 extending outwardly therefrom and engaging a portion of the burner structure. The burner 10 is supported in a horizontal plane and has a downwardly extending air mixing chamber 130 formed integral therewith. Air mixing chamber 130 is conventional and is provided with an adjusting knob 132 which is movable relative to a series of air holes .(not shown) to provide the proper air-gas 'fuel mixture. Valve 16 is supported on wall 126 by a plurality of screws 134 which extend through a plurality of apertures 136 formed in casing 30 and has outlet 43 directly connected to mixing chamber 130 so that the orifice 56 discharges gas directly into the mixing chamber.

A pilot assembly, indicated generally at reference numeral 137, is mounted on a support member 156 connected to burner 10 and comprises a rectangular bracket 138 attached by a plurality of screws 140 to member 156. Standby pilot 18 and igniter pilot 24 comprise a pair of tubes which are connected at one end thereof to bracket 138 by a plurality of fixtures 142 and are respectively connected to gas lines 20 and 26 by conventional connectors 144.

Standby pilot 18 extend-s away from bracket 138 in a horizontal direction and terminates with a deflector 146 disposed-adjacent the open end thereof. Similarly, igniter pilot 24 extends generally away from bracket 138 and terminates with a deflector 148 connected to the outer end thereof. The relative position of standby pilot 18 and igniter pilot 24 is such that a flame at standby pilot 18 is suflicient to ignite any gas flowing from igniter pilot 24. In turn, igniter pilot 24 is so di'sposed that a flame burning thereat causes gas flowing from burner 10-to ignite. The capacity of standby pilot 18 is lower than that of igniter pilot 24 and provides a resultant cool oven. The capacity of igniter pilot 24 is regulated to provide a flame thereat suflicient in size to dispense with any requirement of critical alignment between burner 10 and igniter pilot 24, and provides positive burner ignition.

A support arm 150 is connected at one end to bracket 138 and extends outwardly in a horizontal direction gen erally parallel to that of igniter pilot 24 and standby pilot 18 and terminates in an end member 152 formed with an aperture therein adapted to receive the outer end of capillary tube 82. Capillary tube 82 extends through an aperture in bracket 138 and is connected thereto by a conventional fastener 154. The bulb 78 is disposed adjacent igniter pilot 24 in such a manner that a flame at igniter pilot 24 envelopes substantially all of the bulb 78 and causes rapid heating of the mercury contained therein in response to the ignition of such a flame.

It should be noted that valve 16 is designed with a rela tively short vertical distance near the gas outlet so that the valve 16 may be mounted in ovens that afford only a short distance between the mixing chamber and an oven floor. Furthermore, valve 16 and pilot assembly 137 form a compact assembly which can be readily applied to many various sized ovens and burners.

In operation, when control valve 14 opens, gas flows concurrently to valve 16 and igniter pilot 24. However, since the temperature sensitive means 28 is relatively cool, valve burner 60 remains seated against valve seat 50 to prevent a flow of gas through valve 16. The gas flowing to igniter pilot 24 flows outwardly therefrom and is deflected by deflector 148 and ignited by the flame at standby pilot 18. After ignition, this flame causes temperature sensing means 28 to become heated whereupon, as in the manner previously described, the thermally responsive means causes valve member 60 to open and allow gas to flow through valve 16 to burner 10. The gas, flowing from the burner 10, is ignited by the flame at igniter pilot 24. If there is no flame at standby pilot 18, the thermally responsive means is not actuated and valve member 60 remains closed.

When the burner is lighted, the flame thereat is ordinarily suflicient to maintain the flame at igniter pilot 24 which, in turn, maintains the flame at standby pilot 18. However, if for some reason, the flame at igniter pilot 24 goes out and the flame at standby pilot 18 or burner 10 is insufficient to re-ignite the same, the temperature sensitive means 28 cools with the resultant closing of .valve member 60 and interruption of the flow of the fuel to burner 10. This provides a fail-safe feature. To reset the system, it is necessary to re-ignite the gas flowing from igniter pilot 24.

It will be understood that many changes and modifications in the details of construction and arrangement of parts may be made without departing from the scope of this invention as defined in the appended claims.

I claim:

1. A temperature responsive device comprising an expansible power element, a capillary tube operatively connected at one end thereof to said power element, said capillary tube having a uniform outer diameter and being formed at the other end thereof with a bulb portion comrising a counterbore, said bulb portion having a wall of reduced thickness relative to the wall of said capillary tube, said other end being sealed to form a fluid-tight interior comprising said capillary tube and said power element, a tubular extension welded to the under side of said power element and being in communication with said fluid-tight interior, a charge of temperature sensitive expansible fluid disposed within said fluid-tight interior and being responsive to temperature changes within said bulb portion to cause movement of said expansible power element, and a steel ball welded to form a seal over the open end of said tubular extension and to provide a motion transmitting means for said power element.

. 2. A temperature responsive device comprising an elongated tube having a capillary bore extending substantially throughout the length thereof, said tube being formed with a uniform outer diameter over the length thereof, .one end. of said tube being sealed and having a counterbore adjacent thereto formed of a diameter greater than that of the capillary bore and being in communication therewith, said bulb portion having a wall of reduced thickness relative to the wall of said capillary tube, a pair of flexible diaphragm members operatively connected to one another to form an expansible chamber therebetween, means interconnecting said capillary tube with said diaphragm members whereby said capillary bore communicates with said expansible chamber, a tubular extension welded to the bottom of said expansible chamber and communicating with said expansible chamber, a temperature sensitive fluid disposed within said counterbore, said capillary bore and said expansible chamber and being responsive to temperature changes within said counterbore to cause relative movement of said diaphragm members, and a steel ball welded to form a seal over the open end of said tubular extension and to provide motion transmitting means for said device.

3. In a temperature responsive device, the combination comprising an expansible power element, a capillary tube operatively connected to said expansible element, said capillary tube being formed at the end thereof away from said power element with an enlarged interior chamber having an inner diameter greater than that of the capillary bore, the outer diameter of the tube surrounding said enlarged chamber and said capillary bore being uniform, a tubular extension welded to the under side of said power element and being in communication therewith, a charge of mercury disposed within said capillary bore, said enlarged portion and said power element and being responsive to temperature changes within said enlarged portion to cause movement of said expansible element, a wire disposed within said capillary bore and having a diameter less than that of the bore, and a steel ball welded to form a seal over the open end of said tubular extension and to provide a motion transmitting means for said power element.

4. In a temperature responsive device, the combination comprising a pair of cup-shaped diaphragm members operatively connected about the peripheries thereof to form an expansible chamber therebetween, an elongated tube having a capillary bore extending substantially throughout the length thereof and having a uniform outer diameter throughout the length thereof, said tube being operatively connected at one end thereof to said expansible chamber, a tubular extension welded to the bottom of said expansible chamber and being in communication therewith, a wire disposed within said bore and extending substantially the length thereof, said tube being sealed at the other end thereof and being formed with a counterbore adjacent thereto having a diameter greater than that of said capillary bore, a charge of mercury disposed within the interiors of said tube and said expansible chamber and being operable in response to temperature changes within said counterbore to cause movement of said expansible chamber, and a steel ball welded to form a seal over the open end of said tubular extension and to provide a motion transmit-ting means for said device.

5. A valve for controlling the flow of a fluid fuel to a burner in accordance with the existence of a flame at an igniter pilot associated therewith comprising: a casing formed with an inlet, an outlet, a flow passage therebetween and a valve seat disposed within said flow passage; a valve member movable between positions and cooperable with said valve seat for controlling a fiow of fluid through said casing; a power element disposed within said flow passage; motion amplifying means comprising asupport bracket assembly disposed within said flow path, said bracket having legs provided with fulcrum members positioned thereon; lever means operatively engaging said power element and said valve member for moving said valve member in response to movement of said power element; and thermally sensitive means responsive to a flame at the igniter pilot for causing said power element to move said valve member between positions.

6. In a valve of the class described, the combination comprising a generally elongated casing formed with a longitudinal chamber therein, an inlet communicating with said chamber at one end thereof, an outlet communicating with said chamber at the other end thereof and extending in a direction transverse thereto, and partition means extending across said chamber and being formed with a flow passage therethrough; a valve seat disposed adjacent said flow passage; a valve member movable between positions relative to said valve seat and being cooperable therewith for controlling a flow of gas through said casing; said valve member being reciprocable between an open and a closed position in a plane transverse to said chamber; temperature responsive means having an expansible portion thereof disposed within said chamber, said portion being movable in a direction transverse to the chamber in response to changes in temperature of another portion of said temperature responsive means disposed exteriorly to said casing; and motion amplifying means comprising a U-shaped bracket having downwardly extending legs provided with an upper and a lower fulcrum member positioned thereon, and a lever having one of its ends pivotally engaging the upper of said fulcrum members and the other end engaging one end of a lower lever pivoted about said lower fulcrum member and the other end of said lower lever contacting said valve member for actuating said valve member between positions.

7. A valve of the class described comprising a casing formed with an inlet, an outlet, and a flow passage therebetween, valve means disposed within said flow passage and being movable between positions for controlling a flow of fluid through said casing, an expansible power element disposed within said flow passage, temperature sensitive means operatively connected to said power element and being operable in response to temperature changes for causing said power element to expand and contract, motion amplifying means disposed within said flow passage and being operatively connected between said power element and said valve means for moving said valve means between positions in response to expansion and contraction of said power element, a bracket disposed within said flow passage and being operatively connected to said motion amplifying means for supporting the same within said flow passage, and connecting means operatively engaging said power element and said bracket, said connecting means having a threaded portion and a smooth portion, a shoulder adjacent the smooth portion adapted to underlie said bracket for supporting the same, said threaded portion adapted to pass through said casing and a nut threadedly engaging said threaded portion of said connector for holding the bracket and expansible power element within said flow passage.

8. In a heating system having a gas burner, a mixing chamber connected to the burner for controlling the airgas ratio and gas supply means, the combination comprising: a valve operatively connected between the mixing chamber and the gas supply means and comprising a valve casing formed with an inlet, an outlet, and a flow passage therebetween, valve means disposed within said flow passage and being movable between open and closed positions for controlling a flow of gas through said casing, an expansible power element disposed within said flow passage and being operably connected to said valve means for moving the same between positions; a pilot assembly for controlling the supply of gas to the burner and igniting the same comprising a bracket, a pilot tube mounted on said bracket and extending away therefrom, an igniter tube connected at one end to said bracket and extending away therefrom in the same direction as the pilot tube and having the end thereof disposed adjacent ;the end of the pilot tube whereby a flame burning at said pilot will ignite a flow of gas from said igniter, said igniter being further disposed adjacent the gas burner .to ignite gas coming therefrom when a flame is burning at said igniter, and temperature sensitive means extending through said bracket in a common direction with said pilot tube and said igniter tube and being supported thereby and having a portion disposed within the path of a gas flowing from said igniter, said temperature sensitive means being operably connected to said expansible power element and being operable in response to the existence of a flame at said igniter to maintain said valve means in an open position.

9. In a system for controlling the flow of fuel to a gas burner, the combination comprising a casing having an inlet, an outlet, and a flow passage therebetween, valve means disposed within said flow passage, said valve means including a lever arm for moving said valve means between open and closed positions for controlling the flow of fuel through said casing, an expansible power element disposed within said flow passage and being operably connected said lever arm of said valve means for moving the same between open and closed positions, and temperature sensitive means for actuating said valve to cause said valve means to open to admit fuel to the burner, said temperature sensitive means comprising a capillary tube operably connected at one end thereof to said expansible power element and having the other end thereof formed with a chamber larger than the diameter of the capillary bore forming a bulb portion, saidbulb portion having a wall of reduced thickness relative to a wall of said capillary tube, a tubular extension welded to the under side of said power element and being in communication therewith, and temperature sensitive fluid disposed within said chamber, said capillary bore and said expansible power element and a steel ball welded to form a seal over the open end of said tubular extension, said steel ball being movably engaged with said lever arm of said valve means and operable in response to expansion of said temperature sensitive fluid to cause said valve means to move to one of a plurality of open positions without affecting the value of the friction coefficient between said steel ball and said lever arm.

10. In a heating system having a gas burner disposed horizontally and a mixing chamber operably connected to the burner and extending downwardly therefrom, the combination comprising: a valve for controlling the flow of fuel to the mixing chamber and the burner comprising a valve casing having an inlet, an outlet, and a flow passage therebetween, a throttling orifice formed within said outlet, said outlet being directly connected to the mixing chamber, valve means disposed within said flow passage and being movable between open and closed positions for controlling a flow of fuel through said casing, an expansible power element disposed within said flow passage and being relatively movable between positions, motion amplifying means operatively connected between said power element and said valve means for moving said valve means between positions in response to movement of said power element, an igniter pilot disposed adjacent the burner for igniting gas flowing therefrom, a pilot disposed adjacent said igniter and being operable to ignite gas flowing therefrom, temperature sensitive means disposed in the path of gas flowing from the igniter pilot and being operably connected to said expansible power element for moving the same between positions, and means operably connected to said valve and said igniter pilot for concurrently supplying fuel thereto whereby fuel flowing from said igniter pilot is lit by said pilot flame to cause said valve means to move from a closed to an open position to allow fuel to flow to the burner and be ignited by said igniter pilot.

11. In a heating system having a gas burner disposed horizontally and a mixing chamber operably connected to the burner and extending downwardly therefrom, the combination comprising: a valve for controlling the flow of fuel to the mixing chamber and the burner comprising a valve casing having an inlet, an outlet, and a flow passage therebetween, valve means disposed within said flow passage and being movable between open and closed positions for controlling a flow of fuel through said casing, an expansible power element disposed within said flow passage and being relatively movable between positions, motion amplifying means comprising a U-shaped supporting bracket disposed within said flow passage, a pair of fulcrum members mounted on one of the legs of said bracket, a pair of levers operatively mounted on said pair of fulcrums and an adjusting screw threadedly mounted in one of said levers providing an adjusting means by which the operative range of the power element may be altered, a helical spring extending between said pair of levers biasing said levers apartand into operative engagement with said fulcrums and said levers operatively connected between said power element and said valve means for moving said valve means between positions in response to movement of said power element, an igniter pilot disposed adjacent the burner for igniting gas flowing therefrom, a pilot disposed adjacent said igniter and being operable to ignite gas flowing therefrom, temperature sensitive means disposed in the path of the gas flowing from the igniter pilot and being operably connected to said expansible power element for moving the same between positions, and means operably connected to said valve and said igniter pilot for concurrently supplying fuel thereto whereby fuel flowing from said igniter pilot is lit by said pilot flame to cause said valve means to move from a closed to an open position to allow fuel to flow to the burner and be ignited by said igniter pilot.

12. A temperature responsive device comprising an expansible power element, a capillary tube operatively connected at one end thereof to said power element, and being formed at the other end thereof with a bulb portion, said capillary tube being sealed at said other end thereof, to form a fluid tight interior comprising said capillary tube and said power element, a tubular extension attached to the operative side of said power element and being in communication therewith, a charge of temperature sensitive expansible fluid disposed within said fluid-tight interior and being responsive to temperature changes within said bulb portion to cause movement of said expansible power element, and a ball fastened to form a seal over the open end of said tubular extension and to provide a motion transmitting means for said power element.

References Cited by the Examiner UNITED STATES PATENTS 1,024,729 4/12 Lawler 236-99 X 1,058,171 4/ 13 Froehlich 23699 1,646,548 10/27 Maclaren 236-99 1,751,688 3/30 Eggleston 23699 1,889,792 12/32 Rosenburgh 73368.4 1,956,052 4/34 Te Pas 158-143 1,958,814 5/34 Carson 236-99 1,961,325 6/34 Andersson 23699 2,059,931 11/36 Cate.

2,203,841 6/40 Persons 73368.4 2,327,542 8/43 Matteson 23699 X 2,334,603 11/43 Brumbaugh et al. 158-143 X 2,366,091 12/44 Eskin 73368.4 2,667,217 1/54 Caparone 158-125 JAMES W. WESTHAVER, Primary Examiner.

FREDERICK KETTERER, FREDERICK L.

MATTESON, ]R., PERCY L. PATRICK, Examiners. 

1. A TEMPERATURE RESPONSIVE DEVICE COMPRISING AN EXPANSIBLE POWER ELEMENT, A CAPILLARY TUBE OPERATIVELY CONNECTED AT ONE END THEREOF TO SAID POWER ELEMENT, SAID CAPILLARY TUBE HAVING A UNIFORM OUTER DIAMETER AND BEING FORMED AT THE OTHER END THEREOF WITH A BULB PORTION COMPRISING A COUNTERBORE, SAID BULB PORTION HAVING A WALL OF REDUCED THICKNESS RELATIVE TO THE WALL OF SAID CAPILLARY TUBE, SAID OTHER END BEING SEALED TO FORM A FLUID-TIGHT INTERIOR COMPRISING SAID CAPILLARY TUBE AND SAID POWER ELEMENT, A TUBULAR EXTENSION WELDED TO THE UNDER SIDE OF SAID POWER ELEMENT AND BEING IN COMMUNICATION WITH SAID FLUID-TIGHT INTERIOR, A CHARGE OF TEMPERATURE SENSITIVE EXPANSIBLE FLUID DISPOSED WITHIN SAID FLUID-TIGHT INTERIOR AND BEING RESPONSIVE TO TEMPERATURE CHANBES WITHIN SAID BULB PORTION TO CAUSE MOVEMENT OF SAID EXPANSIBLE POWER ELEMENT, AND A STEEL BALL WELDED TO FORM A SEAL OVER THE OPEN END OF SAID TUBULAR EXTENSION AND TO PROVIDE A MOTION TRANSMITTING MEANS FOR SAID POWER ELEMENT. 